<?
class Encrypt
{
	public static function passport_encrypt($txt, $key) 
	{
		srand((double)microtime() * 1000000);
		$encrypt_key = md5(rand(0, 32000));
		$ctr = 0;
		$tmp = '';
		for($i = 0;$i < strlen($txt); $i++) 
		{
		   $ctr = $ctr == strlen($encrypt_key) ? 0 : $ctr;
		   $tmp .= $encrypt_key[$ctr].($txt[$i] ^ $encrypt_key[$ctr++]);
		}
		return base64_encode(self::passport_key($tmp, $key));
	}
	
	public static function passport_decrypt($txt, $key) 
	{
		$txt = self::passport_key(base64_decode($txt), $key);
		$tmp = '';
		for($i = 0;$i < strlen($txt); $i++) 
		{
		   $md5 = $txt[$i];
		   $tmp .= $txt[++$i] ^ $md5;
		}
		return $tmp;
	}
	
	private static function passport_key($txt, $encrypt_key) 
	{
		$encrypt_key = md5($encrypt_key);
		$ctr = 0;
		$tmp = '';
		for($i = 0; $i < strlen($txt); $i++) 
		{
		   $ctr = $ctr == strlen($encrypt_key) ? 0 : $ctr;
		   $tmp .= $txt[$i] ^ $encrypt_key[$ctr++];
		}
		return $tmp;
	}
}
?>